Revert "Use "SessionHint" enum in ndk API"

Revert submission 21161765-sessionhint_api

Reason for revert: this broke the main-finalization-1 build... somehow. see b/268111957

Reverted changes: /q/submissionid:21161765-sessionhint_api

Change-Id: I2a8b6609729bba06fc9409f4583886915c82577c
1 file changed